A capacitor in the periphery of central processing unit (CPU) used for personal computers and the like is required to have high capacitance and low ESR so as to suppress the fluctuation of voltage and reduce the heat generation at the passing of a high ripple current. As such a capacitor, a chip aluminum solid electrolyte capacitor and a chip tantalum solid electrolyte capacitor are known.
The chip solid electrolyte capacitor is manufactured by producing a solid electrolyte capacitor element where an oxide dielectric film layer, a semiconductor layer and an electrically conducting layer are sequentially stacked to form a cathode part on a surface excluding the anode part at one end of an anode substrate comprising a valve-acting metal foil having fine pores in the surface layer, an anode substrate comprising a sintered body having fine pores in the inside, or an anode substrate comprising this sintered body to which a metal wire is connected, connecting a part of the anode part and a part of the cathode part to an anode terminal and a cathode terminal, respectively, and molding the capacitor element with a jacket while partially leaving outside a part of the both anode and cathode terminals.
In recent years, for increasing the capacitance and further reducing the ESR value of such a solid electrolyte capacitor, there is known a technique of disposing the anode and cathode terminals on the bottom face of a chip solid electrolyte capacitor and molding the capacitor with a jacket while leaving outside only bottom faces of the anode and cathode terminals. When the anode and cathode terminals are disposed on the bottom face of a jacket-molded body, it is expected that the capacitance can be increased by providing the anode substrate fully in the jacket-molded body and low ESR can be achieved by minimizing the distance from the anode and cathode terminals to the anode and cathode parts of the capacitor element.
For example, as shown in a schematic view (perspective view) of FIG. 3, a conventionally known chip solid electrolyte capacitor has a structure that a cathode part (3) of a solid electrolyte capacitor element (1) is provided by stacking a semiconductor layer and an electrically conducting layer in this order on a sintered body comprising a valve-acting metal having formed on the surface thereof an oxide dielectric film layer, a part of the cathode part is placed on a cathode terminal (4), a part of the anode lead (2) (anode part) connected to the sintered body is placed on an anode terminal (5), each part is electrically and mechanically connected, and the entirety is sealed with a jacketing resin while leaving outside only respective bottom faces of the anode and cathode terminals (4a, 5a) to form a jacket (6) (see, JP-A-2003-68576 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”)) (in FIG. 3, for the sake of clear understanding, each of the anode and cathode terminals is drawn by exaggerating the size). Also, JP-A-8-148386 describes a bottom face electrode utilizing the electrode faces provided on top and bottom faces of a substrate.